CBSE Class 12

NCERT Solutions for Class 12 History Chapter 4 Thinkers, Beliefs and Buildings Cultural Developments are part of NCERT Solutions for Class 12 History. Here we have given NCERT Solutions for Class 12 History Chapter 4 Thinkers, Beliefs and Buildings Cultural Developments.

NCERT Solutions for Class 12 History Chapter 4 Thinkers, Beliefs and Buildings Cultural Developments

Question 1.
Were the ideas of the Upanishadic thinkers different from those of the fatalists and materialists ? Give reasons for your answer.
Solution :
The ideas of the Upanishadic thinkers were different from those of the fatalists and materialists. Many ideas found in the Upanishadas show that people were curious about the meaning of life, the possibility of life sifter death and rebirth. There were debates on these issues. The thinkers were concerned with understanding and expressing the nature of the ultimate reality. The ideas such as the nature of the self and the true sacrifice were discussed in Upanishads.

On the other hand, the fatalists believed that everything was pre-determined. Pleasure and pain could not be altered, lessened or increased in the course of Samsara (transmigration). The materialists did not believe in alms or sacrifice or offerings. For them there was no such thing as this world or the next. A human being is made of four elements. When a human being dies the four elements; return to earth, water, fire and air.

Question 2.
Summarise the central teachings of Jainism.
Solution :
The main teachings of Jainism are as follows:
(i) The entire world is animated. Life exists even in rocks and stones normally considered non-living.
(ii) The principle of non-violence is practised in extreme form in Jainism. No harms should be caused to animals, plants and insects and any other living beings that may include rocks and stones too. This is notable that Jains are forbidden to eat late night lest they kill insects by mistake.
(iii) The cycle of birth and rebirth is shaped through Karma. If one is to escape this cycle of Karma, one must practise ascetism and penance. It is possible when one renounces the world. So one has to live in monastery to attain salvation.
(iv) Jain monks have to take vows to observe the following:
(a) Not to kill anyone
(b) Not to steal anything
(c) Not tell lies
(d) Not to possess property
(e) To observe celibacy.

Question 3.
Discuss the role of the Begums of Bhopal in preserving the stupa at Sanchi.
Solution :
The role of the Begums of Bhopal in preserving the stupa at Sanchi was as given below:

• The French sought Shahjehan Begum’s permission to take away the eastern gateway for a museum in France. Englishmen too wanted to do the same. They were not allowed to do so. The French and the English were allowed to prepare plaster-cast copies only.
• Shahjehan Begum and her successor Sultan Jehan Begum, provided money for the preservation of the ancient site.
• Sultan Jehan funded the building of museum as well as guesthouse where persons like John Marshall lived and wrote his important volumes.
• She funded the publication of the volumes.

Question 4.
Read this short inscription and answer :
In the year 33 of the maharaja Huvishka (a Kushana ruler), in the first month of the hot season on the eighth day, a Bodhisatta was set up at Madhuvanaka by the hhikkhuni Dhanavati, the sister’s daughter of the bhikkhuni Buddhamita, who knows the Tipitaka, the female pupil of the hhikkhu Bala, who knows the Tipitaka, together with her father and mother.
(a) How did Dhanavati date her inscription ?
(b) Why do you think she installed an image of the Bodhisatta ?
(c) Who were the relatives she mentioned ?
(d) What Buddhist text did she know ?
(e) From whom did she learn this text ?
Solution :
(a) Dhanavati dated her inscription as in the year 33 of the maharaja Huvishka (a Kushan ruler), in the first month of the hot season on the eighth day.
(b) During the period of Kanishka, the Buddhism was divided into two branches i.e., Hinayana and the Mahayana. The worship of images of the Buddha and Bodhisattas had become an important part of this branch. So, she installed an image of the Bodhisatta in order to enable its followers to worship it.
(c) The relatives, she mentioned, were her father, mother, sister of her mother bhikkhuni Buddhamita.
(d) Tipitaka.
(e) She learnt this text from bhikkhu Bala.

Question 5.
Why do you think women and men joined the sangha?
Solution :
Women and men joined the sangha because within the sangha, all – workers, slaves, wealthy men, gahapatis and kings – were regarded as equal. It was an organisation of monks who could become teachers of dhamma. They shed their earlier social identities on becoming bhikkhus and bhikkhunis. Not only this, the internal functioning of the sangha was based on the traditions of ganas and sanghas where consensus was arrived at through discussions. If that failed, decisions were taken by a vote on the subject.

Question 6.
To what extent does knowledge of Buddhist literature help in understanding the sculpture at Sanchi?
Solution :
Buddhist literature help us upto some extent in understanding the sculpture at Sanchi. It is important that the sculptures at Sanchi depict the teachings of Buddha only. The teachings of Buddha are captured in the literature.

It is notable that Buddha used to roam around among people , preaching them on his teachings. However, he did not claim supernatural power. He told us that the world is ever changing. It is full of sorrows. Sorrow flows out of desire. Buddha asked the followers to take the middle path, not too much of penance, nor too much of indulgence. The literature of Buddhism is useful for the interpretation of the sculpture at Sanchi. People are shown in different moods and in sorrow. Different stages of life are depicted and so on. Hence, it can be stated that Buddhist literature throws valuable light on the sculptures of the Sanchi.

Question 7.
Figs A and B are two scenes from Sanchi. Describe what you see in each of them, focusing on the architecture, plants and animals, and the activities. Identify which one shows a rural scene and which an urban scene, giving reasons for your answer.

Solution :

1. In the figure A, depiction of animals, dead and alive, hunters with bow and arrow, trees have been made. These are one of the finest depictions. Several animal stories have been depicted at Sanchi, the above scene may be one of them. In the second figure B, the images are being worshipped.
2. The scene in the figure A is a rural scene because it contains animals, hunters with bow and arrow and dead animals too. The second scene is an urban scene because it depicts worshipping of images.

Question 8.
Discuss how and why stupas were built. Describe the structure of stupa with example.
Solution :
About 200 years after the time of Buddha King Asoka erected a pillar at Lumbini. This was to announce the visit of Buddha to this place.Stupas were the mounds put on the bodily remains of the body of Lord Buddha or of any object that was used by him. At the place of stupas such objects were buried. These were places of great respect under the tradition of Buddhism, as they had the relics of Buddha. As per the description of Asokavadana winch a famous Buddhist book, Emperor Asoka gave Buddha’s relic to all major cities. Later on such places stupas were put. The most important stupas are at Sanchi, Bharhut and Saranath.

The structure of a stupa was like a dome and hemisphere. On the top of it, there would be a balcony called harmik. This balcony represented the abode of God. The harmik was covered with an umbrella. There used to be railings around the balcony.

The construction of the stupas was made possible by the contribution of many. On the forefront were the monarchs. The Satvahan Kings offered huge amount for the construction of the stupqs. Apart from the monarchs, merchants, artisans and common men and women also contributed to the construction of the stupas.

Question 9.
Discuss how and why stupas were built.
Solution :
(a) The stupas were built to bury the relics of Buddha such as his bodily remains or objects used by him. These were mounds known as stupas. Since they contained relics regarded as sacred, the entire stupa came to be venerated as an emblem of both the Buddha and Buddhism. According to Ashokavadana, Asoka distributed portions of the Buddha’s relics to every important town and ordered the construction of stupas over them.
(b)

• Inscriptions found on the railing and pillars of stupas record donations made for building and decorating them. Some donations were made by kings such as the Satavahanas.
• Some donations were made by guilds such as that of the ivory workers who financed part of one of the gateways at Sanchi.
• Hundreds of donations were made by women and men who mention their names, sometimes adding the name of the place from where they came, as well as their occupations and names of their relatives.
• Bhikkhus and bhikkhunis also contributed towards building the stupas.

We hope the NCERT Solutions for Class 12 History Chapter 4 Thinkers, Beliefs and Buildings Cultural Developments help you. If you have any query regarding NCERT Solutions for Class 12 History Chapter 4 Thinkers, Beliefs and Buildings Cultural Developments, drop a comment below and we will get back to you at the earliest.

Here we are providing NCERT Solutions for Class 12 English Vistas Chapter 8 Memories of Childhood. Students can get Class 12 English Memories of Childhood NCERT Solutions, Questions and Answers designed by subject expert teachers.

Memories of Childhood NCERT Solutions for Class 12 English Vistas Chapter 8

Memories of Childhood NCERT Text Book Questions and Answers

Memories of Childhood Reading with insight

Question 1.
The two accounts that you read above are based on two distant cultures. What is the commonality of theme found in both of them?
Answer:
Both the autobiographical extracts, based upon two distant cultures, depict the lives of two women from marginalised communities who look back at their childhood and reflect on their relationship with mainstream culture. The first account is by an American Indian woman bom in the late 19th century. The account expressed the indignations suffered by the Native Americans at the hands of Christians.

She was ardently against the oppression of Native Americans in Western culture. Though she resented this mistreatment, she still aimed at bridging the wide gap between the dominant white and Native American cultures. She did not let herself get seduced into believing that her Native American traditions were folly or sin.

As a person of mixed blood, her life could be looked upon as an example of the beauty and accomplishments that are possible if the two cultures live in cooperation.The second account is by a contemporary Tamil Dalit writer. She voiced the discrimination she faced as a Dalit. She explored the impact of the discrimination, compounded by the poverty suffered by Dalit women.

The caste system had been so deeply ingrained in the Indian psyche that institutions that ought to promote egalitarianism became the means of perpetuating caste discrimination. Both these accounts are bound by the common theme of discrimination and indignity suffered by women in marginalised communities at the hands of the supposedly superior caste or culture.

Question 2.
It may take a long time for oppression to be removed, but the seeds of rebellion are sowed early in life. Do you agree that injustice in any form cannot escape being noticed even by children?
Answer:
Children are heavily influenced and conditioned by their upbringing. The social influences that they experience from childhood are often ingrained in their subconscious, and are manifested later. Children are also perceptive and keenly aware of positive and negative influences. Rebellious children manifest the ‘seed’ of rebellion planted at some point in their lives.

A sensitive perspective provides a means for understanding how the oppression of children occurs within multiple social contexts that interrelate to produce harmful outcomes for children. Children lack power and resources and are easy targets for adult oppression. Children are exposed to different levels and types of oppression that vary depending on their age, socio-economic class, race, and the beliefs of their parents.

According to the theory of differential oppression, oppression leads to adaptive reactions by children: passive acceptance, exercise of illegitimate coercive power, manipulation of one’s peers, and retaliation. Reducing the oppressive acts of adults and alleviating the damaging circumstances that characterise the social environment of children is critical to reducing the prevalence of juvenile delinquency and other kinds of problem behaviour. The reaction of Zitkala-Sa and Bama to the injustice they perceived as children ranged from defiance, anguish, resentment, and dejection to a fierce determination to excel.

Question 3.
Bama’s experience is that of a victim of the caste system. What kind of discrimination does Zitkala-Sa’s experience depict? What are their responses to their respective situations?
Answer:
Zitkala-Sa was ill-treated and discriminated against from the beginning of her journey. Native Americans, at that time, did not associate with white people and faced discrimination because of their appearance. She felt scared and extremely uncomfortable when unable to comprehend the ways of a foreign culture. Even though she hated the way she was treated, she still had to abide by rules and orders to avoid punishment. However much she suffered at the hands of cultural and racial discrimination, she managed to work her way through and never gave in to discrimination.

Similarly, Bama remained undeterred. She was convinced that she had a role to play. And it was this conviction that made her stand up for her beliefs. She championed the economic and social hardships faced by Dalits due to the discrimination by upper-caste people. Both the writers challenged accepted social practices and did not succumb to pressure. They made their voices heard, and brought to light the indignities faced by their races; they stood by what they believed to be true.

Memories of Childhood Extra Questions and Answers

Memories of Childhood Short Answer Questions

Question 1.
Who was Gertrude Simmons?
Answer:
Gertrude Simmons was an extraordinarily talented and educated Native American woman who struggled and triumphed at a time when severe prejudice prevailed against Native American culture and women. As a writer, she adopted the pen name, Zitkala-Sa. Her works criticized traditional dogma, and her life as a Native American woman was dedicated against the evils of oppression.

Question 2.
What were the first things that upset Zitkala-Sa at school?
Answer:
The severe cold weather and the alien surroundings upset Zitkala-Sa. She was neither familiar with the language nor the strict regime of the hostel. She was perturbed by the sound of the large bell with the annoying the clatter of shoes. Her spirit pined for its lost freedom.

Question 3.
How was the attire of the girls in school different from Zitkala-Sa?
Answer:
The girls at school wore stiff shoes and closely fitted dresses. The small girls wore sleeved aprons and shingled hair. Zitkala-Sa wore soft moccasins, and had wrapped a blanket on her shoulders. She found the tight-fitting clothes rather immodest.

Question 4.
Narrate Zitkala-Sa’s embarrassment at the breakfast table.
Answer:
At the breakfast table, a small bell was tapped, and each of the pupils drew a chair from under the table. Supposing this act meant that they were to be seated, Zitkala-Sa pulled out her chair and seated herself only to realize that the rest were standing. Just as she got up, a second bell was sounded. All were seated at that, and Zitkala-Sa had to crawl back into her chair again. She then heard a man’s voice and saw all had hung their heads over their plates. She saw a pale-faced woman stare at her and dropped her eyes. With the third bell, everyone picked up their knives and forks and began eating. Zitkala-Sa wept as she was confounded by the unfamiliarity of her surroundings and practices.

Question 5.
Why was cutting of her hair the greatest blow to Zitkala-Sa?
Answer:
Zitkala-Sa had been taught by her mother that, in Native American culture, unskilled warriors who were captured had their hair shingled by the enemy. Short hair was worn by mourners, and shingled hair by cowards according to their practices. She tried to resist being shorn of her cultural values.

Question 6.
What were the sights that fascinated little Bama as she walked home from school?
Answer:
Bama enjoyed the entertaining novelties and oddities on the streets, on her way home from school. The performing monkey, the antics of the snake-charmer, the cyclist at his cycle for three days, the Maariyaata temple and the huge bell, the pongal offerings being cooked, the dried fish stall, the sweet stall, the stall selling fried snacks, the street light changing colour, and other such sights fascinated her.

Question 7.
What was that one episode that left an indelible imprint on Bama’s mind?
Answer:
Bama noticed a man holding on to a food packet by its string. Without touching it, he handed it over to the landlord. The landlord opened the parcel and began to eat the vadais. At home, her elder brother explained to how lower cast people, such as the author herself, were prohibited to touch anything of use to the upper caste people. They were believed to sully the item they touched and therefore the package was carefully carried, by its string, for the landlord who belonged to higher caste.

Question 8.
What was the bitter truth of their life that Annan told Bama?
Answer:
Annan told Bama about the caste system that subjugated Dalits in the society. He added that being bom into a lower caste community, one could never get honour or dignity or respect. It was education alone that could help them earn respect.

Memories of Childhood Long Answer Questions

Question 1.
During her first meal in the missionary school, Simmons became painfully aware of the tension between tradition and acculturation and of the great lack of understanding people had about Native American culture. Explain.
Answer:
Before the meal, the girls were lined up. The Indian girls wore stiff shoes and closely clinging dresses, which seemed immodest to the author’s traditional taste. The small girls wore short hair. Simmons walked noiselessly in her soft leather shoes. She was embarrassed as her blanket had been taken off from her shoulders. Just as they entered, the boys came in from the opposite door. She was at a loss when the rest of them prayed, and ate with fork and knife, by the summons of bells.

She noticed the pale-faced woman staring at her and felt unnerved. The writer wept, she was at a loss over the strange practices, she lacked understanding of the western way of dressing, praying and eating. For a child, a sudden change of one’s faith, cultural and aesthetic conditioning is bewildering and often traumatic. The distance between the two cultures is pronounced by the example of the episode. What the west considered barbaric in Native American was the essence and beauty of their culture which was painfully and ignorantly stripped from their personality in an attempt to acclimatize them.

Question 2.
Narrate the trauma Simmons faced as a child during the hair-cutting episode.
Answer:
Judewin, who knew a few words of English, told Gertrude Simmons that they would cut their long, heavy hair. It was a blow to her as in their culture it signified humiliation or mourning. Judewin warned her about the futility of her mission to escape the hair-cutting ritual, but the writer was prepared to struggle. To hide from the situation, she crept up the stairs into a dim, large room, and crawled under the farthest bed in the dark comer. Every time footsteps were heard, she felt terrorized.

She knew that they were searching frantically for her and soon she was dragged out and tied to a chair. She wept loudly but her hair was clipped short. With her hair lost, she lost her spirit. She had suffered a great deal of disgrace earlier and now her hair was cut like that of a coward. She moaned for her mother, but no one came to comfort her. The brutality made her feel like a beast.

Question 3.
Bama like any other child enjoyed innocent pleasures. Justify.
Answer:
The writer walked home from school each day. It was a ten-minute walk but it took her thirty minutes to complete the distance. She would loiter along, watching all the fun and games and all the entertaining new and strange things that she saw on the way. She enjoyed everything, be it the performing monkey, or the snake charmer, or the man who cycled non-stop for days or the spinning wheels. She was fascinated by the Maariyaata temple, its huge bell and the pongal offerings.

She also stopped to hear the political activists, rallying, or to watch a street play, a puppet show, or a stunt performance.Even mundane activities such as waiters cooling coffee, or people chopping onions, or the almond tree with its fruit occasionally blown down held her attention for long. The people selling edibles were equally appealing to her.

Question 4.
Only an untouchable would know the pain of being one. Discuss with reference to Bama’s episode.
OR
How does “Memories of Childhood” bring out the plight of marginalized communities in India?
Answer:
Bama felt and experienced untouchability, early in life. As a child, she noticed an elderly person walking with a small packet, holding on to the packet by its string, without touching it. He brought it to the landlord, bowed low, and extended the packet towards him. The landlord opened the parcel and began to eat the vadais. Her elder brother explained that people believed that they were upper caste and therefore prohibited people from the lower caste to touch them, believing that the act would pollute them.

On hearing that, Bama felt sad and insulted. Her mind rebelled against fetching and carrying for people who considered people such as her untouchable. It made her very angry. She wondered why the upper-caste people behaved in such a manner just because they were richer. She strongly felt that her people must never run errands for those of the upper caste people.

NCERT Solutions for Class 12 History Chapter 10 Colonialism and the Countryside: Exploring Official Archives are part of NCERT Solutions for Class 12 History. Here we have given NCERT Solutions for Class 12 History Chapter 10 Colonialism and the Countryside: Exploring Official Archives.

NCERT Solutions for Class 12 History Chapter 10 Colonialism and the Countryside: Exploring Official Archives

Question 1.
Why was thejotedar a powerful figure in many areas of rural Bengal ?
Solution :
The jotedar was a powerful figure in many areas of rural Bengal due to following factors :

• They had acquired vast areas of land.
• They controlled the local trade including moneylending.
• A large part of their land was cultivated through sharecroppers (adhiyars or bargadars). They brought their own ploughs and worked in the field. After the harvest they handed over half of the produce to the jotedars. They had become rich in the villages.
• Unlike zamindars, jotedars lived in the villages and exercised direct control over poor villagers.
• They resisted efforts by zamindars to increase the jama of the village and prevented zamindari officials from executing their duties.
• They mobilised ryots and deliberately delayed the payments of revenue to the zamindar.

Question 2.
How did Zamindars manage to retain control over their zamindaris?
Solution :
When zamindars were in bad times, they often resorted to various tactics to maintain control over their zamindari. These were in fact their survival tactics. Following are the important ones.

1. Zamindars created fictitious sales during auction. Their own men would make highest bid and later refused to pay up. After repeating this exercise for couple of occasions, the government would be tired and sell it back to zamindar at lesser rate.
2. A part of Estate was often transferred to female members of the family, and that part of property could not be taken by the government any more.
3. Zamindars put hurdle in purchase and occupation of the estate by others by use of sheer muscle power.
4. Sometimes even peasants under the influence of zamindars opposed auction of estate.

Question 3.
How did the Paharias respond to the coming of outsiders ?
Solution :

1. The Paharias were hunters, shifting cultivators, food gatherers, charcoal producers and silkworm rearers. Thus, their life depended on the forest produce. They lived in hutments and considered the entire region as their land. They considered it the basis of their identity as well as survival. They, therefore, resisted the intrusion of outsiders. Their chiefs maintained the unity of the group. They settled disputes and led the tribe in battles with other tribes and . plains’ people.
2. Paharias raided the plains. These raids were necessary for their survival. These were the ways of asserting power over settled communities. It was their means of negotiating political relations with outsiders. Thus to maintain peace, zamindars paid them regular tribute. Similarly, the traders gave them a small amount for permission to use the passes controlled by them.
3. When the British encouraged forests clearance for expansion of agriculture, the raids of Paharias on the settled villages increased. This led to conflict with the British. Ultimately, the Paharias withdrew deep into the mountains, insulating themselves from hostile forces, and carrying on a war with outsiders.
4. After the coming of the Santhals who cleared forests, ploughed land and grew rice and cotton in the areas of lower hills, the Paharias receded deeper into the Rajmahal hills. Thus, it is clear that the Paharias considered outsiders with suspicion and distrust. Every white man appeared to them to represent a power that was destroying their way of life and means of survival, snatching away their control over their forests and lands.

Question 4.
Why did the Santhals rebel against British rule ?
Solution :
The British failed in their attempt to transform the Paharias into settled agriculturists. They, therefore, persuaded the Santhals to settle in the foothills of Rajmahal. They demarcated a large area of land as Damin-i-Koh so that the Santhals might become settled peasants. The Santhals were expected to clear and cultivate one-tenth of the area within the first ten years. Santhals settlements expanded rapidly from 40 villages in 1838 to 1473 villages in 1851. Their population too increased during the same period from 3000 to over 82,000. As a result of it, the revenue for the company increased. The Santhals, who were in search of a place to settle, ultimately got a place and settled in the Damin-i-Koh on the peripheries of the Rajmahal hills.

But they soon found this was not an ideal world for them and they rebelled against the British rule due to the following factors :

• The state was levying heavy taxes on the land that they had cleared for cultivation;
• The moneylenders (dikus) were charging high rate of interest and taking over the land when debt remained unpaid;
• Zamindars were asserting control over Damin area.

Thus, they found that the land was slipping away from their hands. Therefore, to create an ideal world for themselves where they would rule, they rebelled against zamindars, moneylenders and the British. After the revolt (1855-56), the British created the Santhal pargana in the hope to conciliate them.

Question 5.
What explains the anger of Deccan ryots against the moneylenders?
Solution :
The main reasons for the anger of Ryots against moneylenders are as follows:

1. In rural India it was traditional rule that the interest will always remain less than the principal amount. However, in many cases interest payable was more than the principal itself. In one case the interest was Rs 2000 against principal amount of Rs100.
2. No receipt was paid in case of payment of loan partly or fully. This opened the scope of manipulation by the moneylenders.
3. Ryots complained about forging of documents and other fraudulent activity by the moneylenders.
4. Ryots believed that moneylenders were insensitive to them and made an arrogant and exploitative lot.

Question 6.
Why were many zamindaris auctioned after the Permanent Settlement?
Solution :
Under the Permanent Settlement of Bengal 1793, the East India Company had fixed the land revenue that each zamindar had to pay. At the same time, it was stated that the estates of those who failed to pay would be auctioned to recover the revenue. The company fixed the total demand over the entire estate whose revenue the zamindar contracted to pay. The zamindar collected the rent from different villages, paid the revenue to the Company and retained the difference as his income. He was expected to pay the Company regularly. However in practice in the early decades after the Permanent Settlement, zamindars regularly failed to pay the revenue demand and unpaid balances accumulated due to the following reasons :

1. The initial demands were very high because it was felt that under Permanent Settlement, the Company would never be able to claim higher share in case of rise in prices and expansion of cultivation. So in anticipation of such loss high revenue was fixed. It was argued that the burden on zamindar would gradually decline as agricultural production expanded and prices rose.
2. At the time of the settlement, the prices of agricultural produce were low. It made it difficult for the ryots to pay their dues to the zamindar who in return could not pay revenue to the company.
3. The revenue, regardless of the harvest, had to be paid punctually under the Sunset Law.
4. The Permanent Settlement limited the power of the zamindar to collect rent from the ryot and manage his zamindari. The Company had disbanded their troops. Their courts (catcheries) were brought under the supervision of a collector.
5. Rent collection was a perennial problem due to bad harvests and low prices. Some times ryots deliberately delayed payments.

Under the above circumstances, the zamindars could not make payment punctually, and under the Sunset Law, if payments did not come in by sunset of the specified date, the zamindari was liable to be auctioned. This led to auction of many zamindaris after the Permanent Settlement in Bengal.

Question 7.
In what way was the livelihood of the Pah arias different from that of the Santhals ?
Solution :
The livelihood of the Paharias was different from that of the Santhals in the following way:

Question 8.
How did the American Civil War affect the lives of the ryots in India?
Solution :
American Civil War that began in 1860 had a huge impact on the ryots of Deccan region in India. Following events explains how the impact took shape:

1. Britain was the country where large cotton mills were operational. These cotton mills depended on cotton imported from North America.
2. When the USA was reeling under civil war, it was naturally very difficult to import cotton from there.
3. The cotton mills were forced to look for alternative suppliers of cotton apart from US. India made a good option.
4. The farmers in Deccan were encouraged to grow cotton. One way was the easy access of credit. The moneylenders would give credit of Rs 100 for every acre of land under cotton cultivation.
5. The farmers benefitted out of this demand for cotton. But the real beneficiary were the big farmers and traders.
6. However, things changed as normalcy returned to US. Now the demand of cotton in India declined and so declined the easy availability of credit. The ryots fell back to old days of penury and rose in rebellion in many places.

Question 9.
What are the problems of using official sources in writing about the history of peasants?
Solution :
In using official sources for writing the history of peasants, the following problems are faced:

1. The official sources reflect official concerns and interpretations of events. For example, the Deccan Riots Commission was specifically asked to judge whether the level of the government revenue demand was the cause of the revolt. The Commission reported that the government demand was not the cause of peasant anger. It was the moneylenders who were responsible for the riots. Generally, the colonial government never admitted that the discontent was due to government’s policy. In fact, the increase in revenue demand from 50 to 100 per cent was also responsible for the bad condition of the ryots.
2. Official sources explain certain events with exaggeration. For example, the evidence contained in the Fifth Report is invaluable. Researchers, however, indicate that, intent on criticising the maladministration of the Company, the Fifth Report exaggerated the collapse of traditional zamindari power. They also overestimated the scale on which zamindars were losing their land. In fact, zamindaris were auctioned but zamindars were not displaced in every case. In most of the cases, they retained their zamindaris.

Thus, the official sources are written from the point of view of the government. Even Buchanan wrote what he was asked to write by the East India Company. That is why the Paharias viewed him with suspicion and distrust. He was perceived as an agent of the sarkar.

We hope the NCERT Solutions for Class 12 History Chapter 10 Colonialism and the Countryside: Exploring Official Archives help you. If you have any query regarding NCERT Solutions for Class 12 History Chapter 10 Colonialism and the Countryside: Exploring Official Archives, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation

These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation

Question 1.
Name the three important components of biodiversity
Solution:
The three important components of biodiversity are genetic diversity, species diversity and ecological diversity. These components are the basic building blocks of biodiversity. These are intimately linked and may have common elements.

Question 2.
How do ecologists estimate the total number of species present in the world?
Solution:
The diversity of living organisms present on the earth is very vast. According to an estimate by researchers, it is about seven million. The total number of species present in the world is calculated by ecologists by statistical comparison between species richness of a well-studied group of insects of temperate and tropical regions. Then, these ratios are extrapolated with other groups of plants and animals to calculate the total species richness present on the earth.

Question 3.
Give three hypotheses for explaining why tropics show the greatest levels of species richness.
Solution:
The three hypotheses for higher species richness in tropical areas are:

1. Prolong evolutionary time – Temperate areas have undergone frequent glaciation in the past. It killed most of the species. No such disturbance occurred in the tropics where species continued to flourish and evolve undisturbed for millions of years.
2. Favourable environment – There are no unfavourable seasons in the tropics. The continued favourable environment has helped tropical organisms to gain more niche specialisation and increased diversity.
3. More sunlight – More solar energy is available in the tropics. This promotes higher productivity and increased biodiversity.

Question 4.
What is the significance of the slope of regression in a species-area relationship?
Solution:
The slope of regression/regression co-efficient of species-area relationship indicates that species richness decreases with a decrease in area.

• The regression coefficient is between 0.1 – 0.2 regardless of taxonomic group or region, eg: Plants in Britain, Birds in California.
• But in large areas like continents value is eg:- Frugivorous birds, mammals is tropical forests.

Question 5.
What are the major causes of species losses in a geographical region?
Solution:
The major causes of species losses in a geographical area are:

1. Habitat loss and fragmentation
2. Overexploitation
3. Alien species invasion
4. Co-extinctions
5. Disturbance and degradation
6. Pollution
7. Intensive agriculture and forestry.

Question 6.
How is biodiversity important for ecosystem functioning?
Solution:
An ecosystem with high species diversity is much more stable than an ecosystem with low species diversity. Also, high biodiversity makes the ecosystem more stable in productivity and more resistant to disturbances such as alien species invasions and floods.

If an ecosystem is rich in biodiversity, then the ecological balance would not get affected. Various trophic levels are connected through food chains. If anyone organism or all organisms of any one trophic level is illed, then it will disrupt the entire food chain. For example, in a food chain, if all plants are killed, then all deer will die due to the lack of food.

If all deer are dead, soon the tigers will also die. Therefore, it can be concluded that if an ecosystem is rich in species, then there will be other food alternatives at each trophic level which would not allow any organism to die due to the absence of their food resource. Hence, biodiversity plays an important role in maintaining the health and ecological balance of an ecosystem.

Question 7.
What are sacred groves? What is their role in conservation?
Solution:
Sacred groves are forest patches around places of work. These are held in high esteem by tribal communities/state or central government. Tribals do not allow to cut even a single branch of trees in these sacred groves. Preserved over the course of many generations, sacred groves represent native vegetation in a natural or near-natural state & thus is rich in biodiversity & harbour many rare species of plants & animals. This is the reason why many endemic species flourish in these regions.

Question 8.
Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
Solution:

• Control of soil erosion: Plant roots hold the soil particles tightly and do not allow the topsoil to be drifted away by winds or moving water. Plants increase the porosity and fertility of the soil.
• Control of floods: It is carried out by retaining water and preventing runoff rainwater. Litter and humus of plants function as sponges thus, retaining the water which percolates down and gets stored as underground water. Hence, the flood is controlled.

Question 9.
The species diversity of plants (22 percent) is much less than that of animals (72 percent). What could be the explanations for how animals achieved greater diversification?
Solution:
Scientists recorded 22% of plant species diversity including algae, fungi, bryophytes, pteridophytes, gymnosperms, and angiosperms. But they recorded 72% of animal species (including insects, mollusks, fishes, mammals, birds etc.) diversity. Plants have the less adaptive capacity as compared to animals. Animals show locomotory movements and can move from one place to another to suit the environment and also in search of food. On the contrary, plants are fixed. Moreover, animals have well organised body structure with various organs to help adjust to the environment.

Question 10.
Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
Solution:
Yes, there are various kinds of parasites and disease-causing microbes that we deliberately want to eradicate from the earth. Since these micro-organisms are harmful to human beings, scientists are working hard to fight against them. Scientists have been able to eliminate the smallpox virus from the world through the use of vaccinations. This shows that humans deliberately want to make these species extinct. Several other eradication programmes such as polio and hepatitis B vaccinations are aimed to eliminate these disease-causing microbes.

We hope the NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation help you. If you have any query regarding NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter

NCERT Solutions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter are part of NCERT Solutions for Class 12 Physics. Here we have given. NCERT Solutions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter

Question 1.
Find the
(a) maximum frequency, and
(b) minimum wavelength of X-rays produced by 30 kV electrons.
Answer:

Question 2.
The work function of caesium metal is 2.14 eV. When light of frequency 6 x 10¹⁴ Hz is incident on the metal surface, photo emission of electrons occurs. What is the
(а)   maximum kinetic energy of the emitted electrons,
(b)   stopping potential, and
(c) maximum speed of the emitted photo electrons ?
Answer:

Question 3.
The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?
Answer:
V₀ = 1.5 V
∴ Maximum kinetic energy of the emitted electrons,
\(\frac { 1 }{ 2 } m{ V }_{ max }^{ 2 }=e{ V }_{ 0 }=1.5j=15eV\)

Question 4.
Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. The power emitted is 9.42 mW.
(a) Find the energy and momentum of each photon in the light beam.
(b) How many photons per second, on average, arrive at a target irradiated by this beam? (Assume the beam to have a uniform cross-section which is less than the target area), and
(c) How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon?
Answer:
Given, λ = 632.8 nm = 632.8 x 10^-9m
Power, P = 9.42 mW = 9.42 x 10^-3 W


Question 5.
The energy flux of sunlight reaching the surface of the earth is 1.388 x 10³ W/m². How many photons (nearly) per square meter are incident on the Earth per second? Assume that the photons in the sunlight have an average wavelength of 550 nm.
Answer:

Question 6.
In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be 4.12 x 10^-15 V s. Calculate the value of Planck’s constant.
Answer:

Question 7.
A 100 W sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is 589 nm.
(a) What is the energy per photon associated with sodium light?
(b) At what rate are the photons delivered to the sphere?
Answer:
Power of sodium lamp,
P = 100 W

Question 8.
The threshold frequency for a certain metal is 3.3 x 10¹⁴ Hz. If the light of frequency 8.2 x 10¹⁴ Hz is incident on the metal, predict the cut-off voltage for the photoelectric emission.
Answer:

Question 9.
The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?
Answer:

Since the energy of incident radiation less than the work function (4.2 eV) of the metal, therefore, the photoelectric emission can not take place from the given metal. 11.10.

Question 10.
Light of frequency 7.21 x 10¹⁴ Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 x 10⁵ m/s are ejected from the surface. What is the threshold frequency for the photoemission of electrons?
Answer:
Using the relation

Question 11.
Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the cathode, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the cathode is made.
Answer:

Question 12.
Calculate the
(a) momentum, and
(b) de Broglie wavelength of the electrons accelerated through a potential difference of 56 V.
Answer:
Given V = 56 V.
(a) the momentum of the electron

Question 13.
What is the
(a) momentum,
(b) speed, and
(c) de Broglie wavelength of an electron with the kinetic energy of 120 eV?
Answer:
Here, E = 120 eV = 120 x 1.6 x 10^-19J
= 1.92 x 10-¹⁷ J

Question 14.
The wavelength of light from the spectral emission line of sodium is 589 nm. Find the kinetic energy at which
(a) an electron, and
(b) a neutron would have the same de Broglie wavelength.
Answer:

Question 15.
What is the de Broglie wavelength of
(a) a bullet of mass 0.040 kg travelling at the speed of 1.0 km/s,
(b) a ball of mass 0.060 kg moving at a speed of 1.0 m/s, and
(c) a dust particle of mass 1.0 x 10^-9 kg drifting with a speed of 2.2 m/s?
Answer:
(a) Here, m = 0.040 kg and υ = 1.0 km/s .
= 1000 m/s

Question 16.
An electron and a photon each have a wavelength of 100 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electrons.
Answer:

Question 17.
(a) For what kinetic energy of a neutron will the associated de Broglie wavelength be
1.40 x 10-¹⁰ m?  (C.B.S.E. 2008)
(b) Also find the de Broglie wavelength of a neutron, in thermal equilibrium with matter, having an average kinetic energy of \(\frac { 3 }{ 2 } \) kT at 300 K.
Answer:
(a) Here λ = 1.40 x 10^-10m
Also, h = 6.63 X 10^-34 Js
and m = 1.67 x 10^-27kg



Question 18.
Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon).
Answer:

Question 19.
What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root mean square speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076 u)
Answer:
For nitrogen,


Question 20.
(a) Estimate the speed with which electrons emitted from a heated cathode of an evacuated tube impinge on the anode maintained at a potential difference of 500 V with respect to the cathode. Ignore the small initial speeds of the electrons. The ‘specific charge’ of the electron i.e., its elm is given to be 1.76 x 10¹¹ C kg^-1.
(b) Use the same formula you employ in
(a) to obtain electron speed for an anode potential of 10 MV. Do you see what is wrong? In what way is the formula to be modified?
Answer:




Question 21.
(a) A monoenergetic electron beam with an electron speed of 5.20 x 10⁶ ms^-1 is subject to a magnetic field of l.30 x 10^-4 T normal to the beam velocity. What is the radius of the circle traced by the beam, given elm for electron equals 1.76 X 10¹¹ C kg^-1?
(b) Is the formula you employ in
(a) valid for calculating radius of the path of a 20 MeV electron beam? If not, in what way is it modified?
Answer:
(a) υ  = 5.20 x 10⁶ms^_1
B = 1.30 x 10 ⁴T

(b) The formula employed in part (a) is not valid because with the increase in velocity, mass varies and in the above formula we have taken m as constant. Instead, m

Question 22.
An electron gun with its anode at a potential of 100 V fires out electrons in a spherical bulb containing hydrogen gas at low pressure (~ 10^-2 mm of Hg). A magnetic field of 2.83 x 10 ⁴ T curves the path of the electrons in a circular orbit of radius 12.0 cm. (The path can be viewed because the gas ions in the path focus the beam by attracting electrons, and emitting light by electron capture; this method is known as the ‘fine beam tube’ method.) Determine e/m from the data.
Answer:

Question 23.
(a) An X-ray tube produces a continuous spectrum of radiation with its short wavelength end at (45 Å. What is the maximum energy of a photon in the radiation?
(b) From your answer to (a), guess what order of accelerating voltage (for electrons) is required in such a tube.
Answer:

Question 24.
In an accelerator experiment on high-energy collisions of electrons with positrons, a certain event is interpreted as the annihilation of an electron-positron pair of total energy 10.2 BeV into two y-rays of equal energy. What is the wavelength associated with each γ-ray?   (1 BeV = 10⁹ eV)
Answer:
The energy carried by the pair of γ-rays = 10 .2 BeV
The energy of each γ ray is

Question 25.
Estimating the following two numbers should be interesting. The first number will tell you why radio engineers do not need to worry much about photons! The second number tells you why our eye can never ‘count photons’, even in barely detectable light.
(a) The number of photons emitted per second by a Mediumwave transmitter of 10 kW power, emitting radio waves of wavelength 500 m.
(b) The number of photons entering the pupil of our eye per second corresponding to the minimum intensity of white light that we humans can perceive (~ 10^_1° W m^-2). Take the area of the pupil to be about 0.4 cm², and the average frequency of white light to be about 6 x 10¹⁴
Answer:


This is quite a small number, but still large enough to be counted.
Comparison of cases (a) and (b) tells us that our eyes can not count the number of photons individually.

Question 26.
Ultraviolet light of wavelength 2271 A from a 100 W mercury source irradiates a photo-cell made of molybdenum metal. If the stopping potential is -1.3 V, estimate the work function of the metal. How would the photo-cell respond to a high intensity
(~ 10^s W m^-2) red light of wavelength 6328 A produced by a He-Ne laser?
[C.B.S.E. 2005, UC, 13]
Answer:

Since the energy of a red photon is less than the work function for the metal, the photocell does not respond to red light.

Question 27.
Monochromatic radiation of wavelength 640.2 nm (1 nm = 10^-9 m) from a neon lamp irradiates photosensitive material made of caesium or tungsten. The stopping voltage is measured to be 0.54 V. The source is replaced by an iron source and its 427.2 nm line irradiates the same photo-cell. Predict the new stopping voltage.
Answer:

Question 28.
A mercury lamp is a convenient source for studying the frequency dependence of photoelectric emission since it gives a number of spectral lines ranging from the UV to the red end of the visible spectrum. In our experiment with rubidium photo-cell, the following lines from a mercury source were used :
λ_x = 3650 Å, λ₂ = 4047 Å, λ₃ = 4358 Å, λ₄ = 5461 Å, λ₅ = 6907 Å.
The stopping voltages, respectively, were measured to be :
V₀₁ = 1.28 V, V₀₂ = 0.95 V, f₀₃ = 0.74 V, = 0.16 V,V₀₅ = 0 V
(a) Determine the value of Planck’s constant
(b) Estimate the threshold frequency and work function for the material.
Answer:
(a) From the Einstein photoelectric equation,




Question 29.
The work function for the following metals is given : Na : 2.75 eV ; K : 2.30 eV ; Mo : 417 eV ; Ni: 515 eV. Which of these metals will not give photoelectric emission for a radiation of wavelength 3300 Å from a He-Cd laser placed 1 m away from the photocell? What happens if the laser is brought nearer and placed 50 cm away? (C.B.S.E. 2009)
Answer:
Here, λ = 3300 A = 3300 x 10^-10 m
Distance, r’ = 1 m and r’ = 50 cm = 0.5 m
Using the relation

Since the energy E of the incident photon of light is less than the work functions of Mo and Ni metals, so photoelectric emission will not occur in Mo and Ni. The distance of the source does not increase or decrease the energy of the photon of the light incident, therefore, the energy of electrons ejected will not change but the intensity of ejected electrons will increase (1 α 1/r² ) and become four times.

Question 30.
Light of intensity 10^-5 W m^-2 falls on a sodium photo­cell of surface area 2 cm². Assuming that the top 5 layers of sodium absorb the incident energy, estimate time required for photoelectric emission in the wave- picture of radiation. The work function for the metal is given to be about 2 eV. What is the implication of your answer?
Answer:
A = 2 cm² = 2 x 10^-4 m²
φ = 2eV = 2 x 1.6 x 10^-19 J
= 3.2 X 10^-19  J.
Taking the approximate radius of an atom as 10^-10 m. the effective area of sodium atom is ≈ r² = 10^-20 m.
.’. If there is one free electron per atom, then the number of electrons in five layers


The answer obtained implies that the time of emission of the electron is very large and is not in agreement with the observed time of emission, which is approximately 10 ⁹ s. Thus wave-picture of radiation is not applicable for photo-electric emission.

Question 31.
Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage. Which probe has greater energy? (For quantitative comparison, take the wavelength of the probe equal to 1 Å which is of the order of interatomic spacing in the lattice) (m_e = 9.11 x 10^­-31 kg).
Answer:

Clearly, the energy of photons is much greater than the energy of electrons.

Question 32.
(a) Obtain the de Broglie wavelength of a neutron of kinetic energy 150 eV. As you have seen in Exercise 44, an electron beam of this energy is suitable for crystal diffraction experiments. Would a neutron beam of the same energy be equally suitable?
Explain. (m_n = 1.675 x 10^-27 kg).
(b) Obtain the de Broglie wavelength associated with thermal neutrons at room temperature (27°C). Hence explain why a fast neutron beam needs to be thermalized with the environment before it can be used for neutron diffraction experiments.
Answer:

This wavelength is about hundred times smaller than the interatomic separation of crystals. Thus, neutrons are not suitable for diffraction experiments in case of crystals.

This wavelength is comparable to the interatomic spacing of crystals. Therefore, thermal electrons are able to interact with the crystal. Since

increasing the temperature, decreases their de Broglie wavelength and they become unsuitable for crystal diffraction. Thus, the fast beam of neutrons needs to be thermalised with the environment for neutron diffraction experiment.

Question 33.
An electron microscope uses electrons accelerated by a voltage of 50 kV. Determine the de Broglie wavelength associated with the electrons. If other factors (such as numerical aperture, etc.) are taken to be roughly the same, how does the resolving power of an electron microscope compare with that of an optical microscope which uses yellow
light ?
Answer:



Question 34.
The wavelength of a probe is roughly a measure of the size of a structure that it can probe in some detail. The quark structure of protons and neutrons appears at the minute length-scale of 10^-15 m or less. This structure was first probed in early 1970’s using high-energy electron beams produced by a linear accelerator at Stanford, USA. Guess what might have been the order of energy of these electron beams. (Rest mass energy of electron = 0.511 MeV).
Answer:

Thus, the energy of the proton ejected out of the linear accelerator is of the order of BeV.

Question 35.
Find the typical de Broglie wavelength associated with a He atom in helium gas at room temperature (27 °C) and 1 atm pressure, and compare it with the mean separation between two atoms under these conditions.
Answer:
Here T = 27 °C = 27 + 273 = 300 K
P = 1 atm = 1.01 x 10⁵ Nm^-2
Also, the mass of helium atom,


Question 36.
Compute the typical de Broglie wavelength of an electron in metal at 27°C and compare it with the mean separation between two electrons in a metal which is given to be about 2 x 10^_10 m.
Answer:
Here, T = 27°C = 27 + 273 = 300 K


Question 37.
Answer the following questions:
(a) Quarks inside protons and neutrons are thought to carry fractional charges [(+2/3) e; (- l/3)e]. Why do they not show up in *Millikan’s oil-drop experiment?
(b) What is so special about the combination elm? Why do we not simply talk of e and m separately?
(c) Why should gases be insulators at ordinary pressures and start conducting at very low pressures?
(d) Every metal has a definite work function. Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic? Why is there an energy distribution of photoelectrons?
(e) The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relations :

Answer:
(a) In case of the Millikan oil-drop experiment, the charge on the electron is measured. The electron revolves outside the nucleus and each has a charge e. Thus, we do not observe the fractional charges

(c) At ordinary pressure, molecules of gas keep on colliding with each other and the ions formed do not have a chance to reach the respective electrodes to constitute a current because of their recombination. At low pressure, however, ions do not collide frequently and are able to reach the respective electrodes to constitute a current.
(d) Work function in fact is the energy required to knock out the electron from the highest filled level of the conduction band of an emitter. In the conduction band, there are different energy levels which collectively form a continuous band of levels. Therefore, different amounts of energy are required to bring the electrons out of the different levels. Electrons emitted have different kinetic energies according to the energy supplied to the emitter.
(e) Since frequency for a given matter-wave remains constant for different layers of the matter but wavelength changes so X is more significant than v.
Similarly energy E = hv = \(\frac { 1 }{ 2 } \) m(λv)² is also constant for a given matter wave so phase λv is also not physically significant.

We hope the NCERT Solutions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter, help you. If you have any query regarding NCERT Solutions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter, drop a comment below and we will get back to you at the earliest.